The importance of titanium, in the manufacture of air frame and space-craft structures, for example, because of its superior heat resistance, high strength, and relatively light-weight, is now well established. Along with the use of titanium in sheet form, forgings, and stampings, titanium is a promising candidate for wide use in high-strength, lightweight laminated structures and composite assemblies fabricated by weld-bonding, diffusion bonding, and adhesive bonding.
It is also well recognized in the metal processing field that it is difficult to bond titanium to other materials, as in sandwich or composite structures, because organic adhesives do not bond well to titanium. Thus a number of special processes for preparing the surface of titanium for adhesive bonding heretofore have been proposed, which processes, however, tend to be relatively complex, time-consuming, and expensive. Time and expense are important considerations, and especially so in the mass production of aircraft, spacecraft, and automobiles, for example.